Treatment of fabric containing cellulose esters



No Drawing.

Patented Oct. 25, 1932 UNITED STATES PATENT OFFICE QAMILLE DREYFUS, OF NEW YORK, N. Y., AND GEORGE SCHNEIDER, OF EAST ORANGE,

NEW JERSEY, .ASSIGN'ORS TO TION OF DELAWARE CELAE'ESE CORPORATION OF AMERICA, A CORPORA- TREATMENT OF FABRIC CONTAINING CELLULOSE ESTEBS This invention relates to the treatment of textile materials such as yarn or fabric containing organic esters of cellulose, and particularly cellulose acetate, with a paste containing an alkaline agent in such a manner that the safe ironing point of the same is appreciably increased, the textile material is rendered capable of being dyed with cotton o dyes, and other of its properties are improved.

An object of our invention is to treat yarns or fabrics containing organic esters of cellulose with a pasty mass containing alkaline material in such a manner that the yarn is saponified on the surface of the filaments whereby the temperature at which the yarn or fabric may be ironed is considerably increased.

Another object of our invention is to treat textile materials containing organic esters of cellulose with a paste containing alkali in such concentration and in such a manner that the textile material may be dyed with dischargeable colors, whereby discharge prints may be readilyproduced on the textile material so treated. Other objects of our invention will appear from the following detailed description.

Fabrics containin organic esters of cellulose, and particular y cellulose acetate, must be ironed or calendered at a comparatively low temperature, since if the iron or calender is above about=220 0., sticking of the fabric to the same, and melting of the cellulose acetate is liable to result. Furthermore, the discharge printing on fabrics containing organic esters of cellulose to produce light figures on dark backgrounds has heretofore ofiered serious difficulties. This is due to the fact that the dark colors such as reds, blues and blacks that are" available for the dyeing of cellulose acetate fabric cannot usually be discharged by the ordinary color discharging agents.

We have discovered that if yarns or fabrics containing organic esters of cellulose, such as Application filed July 28,

1928. Serial No.,298,094.

tion of the filaments takes place on the surface of the yarn or filament of the organic esters of cellulose, so that a fabric is produced whose safe ironing point is raised to 250 to 260 C. I

or more. Moreover, the fabric when treated by our process is capable of being dyed with cotton dyes that may be discharged by printing pastes containing ordinary discharging agents.

Because of the fact that the saponification is concentrated on the surface of the filaments or yarn, the textile material produced has substantially all the desirable properties of untreated textile material containing organic esters of cellulose.

In accordance with our invention, we treat fabrics or yarn containing organic esters of cellulose with a pasty mass containig a solution of alkaline material and a thickening agent in any suitable manner. The paste may contain, if so desired, direct cotton dyes that are not affected by alkalies.

The fabric or yarn to be treated may .contain any organic esters of cellulose such as cellulose acetate, cellulose formate, cellulose capable of producing hydroxyl ions in aqueous solution. Of the alkalies we have found sodium hydroxide, potassium hydroxide and ammonium hydroxide to be suitable. Examples of suitable alkaline salts are sodium carbonate, potassium carbonate, sodium phenolate, potasium phenolate, sodium silicate, potassium silicate, sodium sulphite, potassium sulphite, trisodium phosphate or tripotassium phosphate." Any one or a mixture of two or more of these alkaline materials may be used. In order to promote surface saponification, the paste may also contain buffer salts or modifying agents such as soap, sodium acetate, borax or ethyl alcohol. The amount of alkaline material that we prefer to emplo corresponds in amount to 1 to 10% and re erably 3, 4 to 5% of caustic soda base on the weight of the pasty mass.

Any suitable thickening agent may be used in the paste, examples of which are gum tragacanth, gum tragasol, dextrine, British gum, water soluble cellulose ethers, starches or gum arabic. Instead of using a gelatinizable material as the thickening agent, mineral substances such as fullers and infusorial earth may be employed, but these are not preferred.

The alkaline paste may be applied by printing rolls either locally but preferably over the whole surface by means of pin rolls or pad rolls in any suitable manner. The paste may also be applied by brushing or spraying or by any other method for coating textile material with a paste.

After the composition containing the alkaline material is appliedto the fabric, the same is quickly dried by passing the same over heated drums, through a dryer or in any other desired manner, and the fabric may then be steamed at such temperature and for such time as to obtain the required degree of saponification. The amount of alkali apphed is suflicient to cause saponification of the organic ester material, say to the extent of 3% or 5% to or more, up to as measuredrelg' the loss of weight the material has sufie during the saponification. The fabric or yarn, after treatment by our procases, has a safe ironing point of 250 to 260 C. or more and is intensel saponified on the surface. By .intense su ace saponification is meant the concentration of saponification of the cellulose ester material on the surface of the yarn, while the interior of the yarn is very little affected, and, therefore, consists essentially of cellulose esters. This is indicated by the fact that when cellulose acetate fabrics are treated in accordance with the above described methods, the solubilityof the fabric in acetone is relatively hi h, and

' the fabric may be dyed with cotton yes because of the fact that the surface of the yarn is essentially reconstituted cellulose or approximately so. thThe fabric, after it has been treated with e sa nifymg' paste by an of the above as above indicatedyis capable of bemg dyed by dyedufis that have an aflinity for cellulose acetate but not for cotton, such as are known as SRA dyes,.and also by dyes that have an afinity for cotton, but not for cellulose acetate, such as direct cotton dyes and basic dyes, because of the intense surface saponification of the yarn. The direct cotton colors available for dyeing this material are within all ranges of colors. These cotton dyes include blues, blacks and reds, which may be discharged by ordinary discharge printing pastes, and therefore discharge prints of dark backgrounds may be produced on this fabric,a result heretofore not readily attainable on fabrics containing cellulose acetate yarn.

The fabric, so treated and after having been dyed with direct cotton dyes, may be printed with a discharge paste which contains a reducing agent, and which may or may not contain colors for printing the discharged portions. After printin with the discharge paste, the fabric may be steamed and given other treatments as is well understood in the art.

The discharge paste may be applied in any suitable manner, such as by means of engraved or embossed rolls, plates or blocks. The paste may also be applied through stencils by means of brushing or spraying. The

hydrosulphite or formaldehyde hydrosul-.

phite are preferred, 'whereas if a colored discharge is desired the protolin is preferred.

In order further to illustrate our invention the following specific example is given.

Example A woven fabric consisting wholly of cellulose acetate yarn has applied thereto over its entire surface either one of the following pastes.

Paste A Parts by weight Gum tragacanth thickening containing 6% of gum tragacanth 50 Water 40 Caustic soda 4 Paste B Parts by weight British gum thickening 20 (7 parts by weight of the gum and 5 parts of water) Water 10 Caustic sod 0. 7

Paste!) Parts by weight Gum arabic thickening 11 Water V 40 Caustic soda 4 The paste may be applied on a printing machine by means of a pin roller or an all engraved roller or by any suitable device for applying the paste to the entire surface of the fabric. The printed fabric is then immediately passed over drying drums to dry the paste, and is then steamed for 20 minutes with steam at 5 pounds pressure. The fabric thus produced has asafe ironing point of 260C. and has an affinity for cotton dyes as well as cellulose acetate dyes. It may be finished in any. desired manner. If desired, the fabric ma be dyed with direct cotton dyes and then disc arged printed. It may also be printed or dyed in any desired manner.

It'is to be understood that the foregoing detailed description is given merely by way crease substantially the safe ironing point thereof. 1

' 2. Method of increasing the safe ironing point of fabric containing cellulose acetate filaments comprising applying to the whole surface thereof a paste containing a thickening agent and an alkaline material in amounts to cause surface saponification of said cellulose acetate filaments to increase substantially the safe ironin point thereof.

3. Method of increasing t e safe ironing point of fabric containing organic ester of taining a thickening agent and an alkaline material in amounts to cause surface saponification of said organic ester of cellulose filaments to increasesubstantially the safe ironing point thereof and then quickly drying the same.

In testimony whereof, we have hereunto subscribed our names.

CAMILLE DREYFUS. GEORGE SCHNEIDER.

cellulose filaments comprising applying to the whole surface thereof a paste containing a thickening agent and an alkaline material in amounts to cause surface saponification of said organic ester of cellulose filaments to increase substantially the safe ironing point thereof and then quickly drying the same.

4. Method of increasing. the safe ironing point of textile material containing organic esterof cellulose filaments comprising applying tothe whole surface thereof a paste contaming a thickening agent and an alkaline material in amounts to. cause surface saponification of said organic ester of cellulose filaments to increase substantially the safe ironing point thereof.

5. Method of increasing the safe' ironing point of textile material containing cellulose acetate filaments comprising applying to the whole surface thereof a paste contamin a thickening agent and an alkaline materia in amounts to cause surface saponification of said cellulose acetate filaments to increase substantially the safe ironin point thereof.

6. Method of increasing t e safe ironing point of textile material containing organic ester ofcellulose. filaments comprising applying to the-whole surface thereof a'paste con- 

